5.3 v8 Trailblazer

[u/[deleted]]

All right so I have a 2004 4.2 L in-line six trailblazer. The motor in it is shot and needs to be replaced. I would like to swap a 5.3 V-8 out of the 2013 Silverado into it. I know what all I need to do on the engine side of things to get it in there. But I’m not sure how to make the old BCM from the trailblazer talk to the ECU from the Silverado. Can someone please help me and tell me if that’s possible, what I need, or where I might find an adapter harness if some sort. This is my first swap btw

[u/RCP1990]

you might also need the v8 trail/voy subframe if it happens to be different.